Systemic lupus erythematosus (SLE) is a complex autoimmune disease with a broad spectrum of clinical manifestations affecting several organs and associated with dysregulation of the immune system. This disease affects millions of individuals, with women and underserved minorities disproportionately burdened. It is associated with significant morbidity and mortality, yet treatment approaches remain broadly immunosuppressive, anti-inflammatory, or palliative. Despite the considerable progress on understanding SLE immune-pathogenesis, only one drug has been approved for the treatment of lupus patients in the last 50 years, emphasizing the urgent need for novel therapies. Considering the central role of auto-antibodies in the amplification of auto-immunity, a goal in lupus therapy is the elimination of auto-reactive antibody secreting cells (ASC). Karyopharm Therapeutics has pioneered the development of Selective Inhibitors of Nuclear Export (SINE) compounds, and wishes to investigate their potential utility in auto-immune diseases. In collaboration with the Anolik laboratory at the University of Rochester Medical Center, we will evaluate a novel approach to the treatment of autoimmune disease that targets the generation and survival of autoreactive plasma cells (PCs) via inhibition of nuclear export. SINE compounds have a potent effect on the generation of splenic T follicular helper cells (TFH) and germinal center (GC) B-cells, and selectively inhibit production of auto-reactive ASCs specific for double stranded DNA. SINEs had a compelling effect on GC formation/stability, prevented expansion of memory TFH and B cells, and markedly reduced mRNA expression of molecules critical for survival and recruitment of auto-reactive ASC including certain cytokines, interleukin and interferon induced chemokines. Thus, SINE drugs strongly and selectively ablated auto-reactive PCs by targeting pathways that are critical for their generation and survival/recruitment into inflamed kidneys. In the proposed project, we will define the efficacy of SINE compounds in SLE in order to accelerate the translation of these novel compounds into lupus clinical trials. In Aim 1, we will identify the optimal treatment strategy of SINE compounds in murine SLE model by (i) refining the dose and time required for GCs and PCs to exhibit a response in vivo, (ii) optimizing the induction treatment strategy, and (iii) determining the duration of SINE compound effect and define the need for maintenance therapy. In Aim 2, we will examine the protective immunity effects of the SINE compounds by (i) evaluating the immune responses in murine SLE during treatment and (ii) determining the recovery of protective immune responses after cessation of therapy. Successful completion of these studies will lead to a Phase II proposal to move SINE compounds into extensive preclinical safety testing in preparation for clinical trials. The goal is to develop an efficacious dosing strategy using a novel treatment approach that targets key synergistic pathways in SLE disease pathogenesis, with the long term goal of delivering an improved therapy for SLE and other autoimmune diseases.